A grading system for the quality of hardcopy color prints is suggested. It uses two index numbers: one of them describes the size of the available color space in terms of psychooptical discriminability; the other describes the size of the digitization error with respect to the detection threshold. Several examples illustrate the grading system developed at the Lehrstuhl Feingeratebau of the Technical University of Munich. In the CIELAB color space the number of printable and distinguishable colors is determined. It can be approximately calculated from the gamut values and the contrast of black and white. The number can be used as a color quality number for comparisons between hardcopy devices. A typical color inkjet printer now available on the market and using the recommended paper reaches about half the size of the color solid available in offset-printing. Digitization errors are brought in relation to the detection threshold. Contouring, texture, and positioning errors are examined separately in the frequency domain. The overall print quality is determined by the largest error beyond the detection threshold. The psychooptical basics of assessing digitalization errors are summarized. The influences of the dither method and of the halftoning cell are described. The connections between halftoning method, print resolution, and visibility of digitalization errors are shown. Orthogonal halftoning cells are compared to hexagonal cells. Improvements by using different dot sizes and presentation modes are discussed.